Security Audit

A Detailed Guide to Android Penetration Testing

Updated on: November 20, 2021

A Detailed Guide to Android Penetration Testing

For a long time, android applications have been the most popular choice of users over desktop applications. The reason is simple – it is easy to use and user-friendly. Moreover, there is a wide variety of applications available for Android devices. Android purpose-built application development is one of the most prominent choices for business owners and mobile app developers since Android is the world’s most popular mobile operating system.

Introduction

Insecure Android applications pose a threat to the users’ privacy and security. Moreover, such apps can also result in financial losses. This is mainly because of the openness of the Android ecosystem. Mobile applications are more vulnerable to cyberattacks than ever before. One of the best ways to improve the security of an android app is to perform android penetration testing.

This blog post will explain how vital android penetration is, how it helps companies be secure from hackers and cyber-criminals, and much more about android penetration testing in detail.

What is Android Penetration Testing?

Android penetration testing is a process of finding security vulnerabilities in an android application. It is a systematic approach to searching for weaknesses in an Android app, verifying the app’s security, and making sure it abides by the security policies. It includes trying to attack the android application by using various methods and tools. 

The primary aim of android penetration testing is to find the vulnerabilities in the application and fix them before cybercriminals exploit the vulnerabilities. The security issues are mainly related to data theft, information leakage, etc. The android penetration testers generally do the android application penetration testing.

Make your mobile application the safest place on the Internet

with our detailed and specially curated web app security checklist.

Understanding Architecture of an Android App

An APK file is an archive file, and its primary use is to distribute the application’s binary files to the end-user. The APK file is a separate file from the Android operating system. Applications are installed on Android devices through the APK file, which is installed on the device’s system partition.

Check out the architecture of a decompiled APK file mentioned below:

Architecture of APK file
Image: Architecture of APK file

Why is Android Penetration Testing essential?

In today’s world, android apps are used for multiple reasons, such as mobile banking, shopping, sharing personal details, social networking, and entertainment. The android devices are prone to threats from various hacking techniques, such as buffer overflow, code injection, reverse engineering, malware, etc. 

The identification and penetration testing of the vulnerabilities in the android applications to identify and resolve the weaknesses in the applications is referred to as Android penetration testing. 

Some of the benefits of the android penetration testing are:

  • Uncover security risks of android applications.
  • Improve the efficiency of the application.
  • Gaining customer trust
  • Decrease cost of the data breach
There are total of 3.48 million apps making it biggest app store
Image: Did you know?

What is OWASP Mobile Application Security Project?

The Open Web Application Security Project (OWASP) has been a global charitable organization working to make the web a safer place. 

The OWASP Mobile Security Project includes a list of the top ten security risks that mobile applications face today. Each of the top ten mobile security risks is ranked by its threat level and further investigated. Let’s understand each one of these in detail:

M1: Improper Platform Usage

Improper Platform Usage is a risk that is very important to identify. This is because it can have a significant impact on your data or devices. This risk involves the misuse of an operating system feature or a failure to use platform security controls properly. 

This may include Android intents, platform permissions, the Keychain, or other security controls that are part of the platform.

M2: Insecure Data Storage

Data security can be defined as the security surrounding any data that is stored or transmitted. Data of android applications are stored in various locations like servers, mobile devices, and cloud storage. All of these locations are susceptible to attacks by hackers. To protect the data from these attacks, the data needs to be stored securely.

M3: Insecure Communication

 Insecure communication is sending sensitive data over non-secure channels. When sending data over non-secure channels, it can be intercepted by anyone who has access to this channel, which is everyone on the same network. 

This means that if you are sending sensitive data, the data can easily be copied. This is very common in public WiFi access points. When using public WiFi access points, you should always assume that your data is being intercepted.

M4: Insecure Authentication

Authentication is a mechanism to prove a user’s identity to a system. It is also a process of initializing and maintaining a “state” on the system (e.g. a session or a login state), which can be used to determine the user’s identity. 

Weak authentication is one of the root causes of many security risks. Attack vectors such as authentication bypass, information disclosure via debug messages, session invalidation are typical examples of insecure authentication.

M5: Insufficient Cryptography

While cryptography is a fundamental part of any app that stores user data, there is a common misconception that cryptography can solve all security problems. Cryptography is just a tool that helps to protect the data from attackers. 

If any weak point is found in the cryptographic implementation, an adversary can still access sensitive information. In this blog post, we will walk you through the most common cryptography mistakes and how to avoid them. 

M6: Insecure Authorization

Authorization is a process that ensures that only authorized individuals who are allowed to access the data are performing the access operation. Authorization is a crucial aspect of the CIA triad. Many mobile applications have improper authorization implemented due to which low-level users can access information of any high privileged user.

M7: Client Code Quality

Application code quality is the essential factor in ensuring the quality of the final product. As a developer, you should have several goals for your application. Many security flaws can occur in a mobile application, but the most common ones are SQL Injection, Cross-Site Scripting, and Buffer Overflows. The reason why these security flaws occur is because of the poor quality of the client code.

M8: Code Tampering

Code tampering is a process in which hackers or attackers exploit the existing source code of an application by modifying it with malicious payloads, which can lead to business disruption, financial loss, and loss of intellectual property. 

The issue is usually found in the mobile apps that are downloaded from third-party app stores. These app stores are not associated with the official mobile application developers and usually distribute pirated apps. 

M9: Reverse Engineering

Reverse Engineering is a process to decompile the mobile application to understand the application logic. Code obfuscation is done to prevent attackers from reading the application code and understanding the logic.

M10: Extraneous Functionality

Bad actors such as cyber-criminals or hackers try to understand the mobile application’s extraneous functionality. The main goal is to understand and explore hidden functionalities of the backend framework.

Make your mobile application the safest place on the Internet

with our detailed and specially curated web app security checklist.

SSL Pinning: What and Why?

The SSL pinning is a process of ensuring that the communication between the application and the server is encrypted using robust cryptographic algorithms. The communication is only possible if the server uses the correct certificate or Public Key. 

SSL pinning is used to prevent the Man in the Middle (MIM) attack. This attack is possible when an attacker can communicate between the end-user and the server. The attacker can then record the communication between the end-user and the server. This is known as the man-in-the-middle attack.

Understanding SSL Pinning for Android Penetration Testing
Image: SSL Pinning for Android Penetration Testing

Focus Areas for android penetration testing

1. Data Storage

Testing for storage of data in an android application is an integral part of android penetration testing. These tests should include:

  • Checking for Hardcoded credentials
  • Sensitive data exposure such as API keys or tokens
  • Encryption and Weak cryptography

2. Application-level communication

Communication of application with other applications and with the application’s servers can lead to critical security issues if the communication between can is not done via a secure channel. Hackers use man-in-the-middle attacks to intercept the communication between mobile applications and servers.

3. Debug and Error messages

While developing an android application, developers use different kinds of error or debug messages to understand different application-level errors. These error messages are usually left even after production.

Hackers use these error messages to understand the flow of the application and hidden functionalities of the application.

4. Authentication & Authorization

Authentication and authorization are key areas to test while performing android penetration testing. These tests should include:

  • Session related security issues
  • Storage of session token
  • Authentication checks on sensitive endpoints
  • Improper access controls

5. Code Obfuscation

The process of obscuring code to conceal its purpose is known as code obfuscation. Obfuscation leads to a code that is difficult to reverse engineer. Obfuscation is used as a method of protecting intellectual property as well as for anti-tampering. 

Obfuscation is done by adding meaningless symbols (such as variable names like $i), changing the order of operations (i.e. changing the order of mathematical operations), or by using different languages (for example, by using a hexadecimal or other representations)

Related Blog – A Deep Dive into Mobile Application Penetration Testing

5 Secure Coding Practices for Android Developers

1. Communication over HTTPs

Communicating over HTTPs is not a new concept for the web. It’s something that should be standard practice for any business or company. The only problem with using HTTPs is that it isn’t an option everyone can use. It requires modification to your current infrastructure while it also requires you to re-enroll into your SSL certificate. 

Even though the benefits of using HTTPS are apparent, plenty of companies still don’t use it. The argument for using HTTPs is usually the same: it’s not worth the cost, or it’s not an option. However, the argument shouldn’t be whether or not it’s worth the cost, but if using HTTPs will improve your business, which it will.

2. Encrypting sensitive data

Data encryption is the process of changing information to make it unreadable without secret information or a key known only to authorized parties. Encryption is used to protect data so that unauthorized parties cannot read it. 

Data encryption can be used to protect data travelling between two computers over the Internet, or it can be used to protect data stored on a hard drive. Data encryption can be used to protect data from being read or changed by malicious programs. Encrypted data is locked up in a way that only authorized parties can access it.

3. Ask for credentials before showing sensitive information

 Secure android applications use data masking and password or biometric-based authentication to show or display sensitive data such as API Keys.

4. Use common error messages

As discussed earlier, error messages can lead to the discovery of hidden functionalities of the application. To avoid these security risks, developers should use common error messages and remove the debug errors or logs once the app is live.

5. Check the validity of external data sources

External storage can be used to store data that are used by your application. This can include data about your application, such as a list of the most recent documents opened by the user or data that your application uses to do its work, such as a database containing a list of customers. 

The issue here is that you have to make sure that the data stored in external storage hasn’t been corrupted or modified by anyone else.

Top 3 open source tools for android penetration testing

Android penetration testing is done via the various number of tools but let’s check the top 3 tools that are usually used:

  1. MobSF: MobSF is an automated, all-in-one mobile application (Android/iOS/Windows) pen-testing, malware analysis and security assessment framework capable of performing static and dynamic analysis.
  2. Frida: Frida is a dynamic instrumentation toolkit that is used by developers, reverse-engineers, and security researchers
  3. Apktool: Apktool is used for reverse engineering/decompiling any apk file. Using various Linux commands, android penetration testers find sensitive data.

It’s one small security loophole v/s your Android & iOS app

Get your mobile app audited & strengthen your defenses!

What is Astra’s Android Pentest Suite?

Astra’s pentest suite is a complete solution to all your security needs. Astra makes it easy to perform controlled attacks on android devices with an easy-to-use interface and a streamlined workflow.

At Astra, we understand your needs and keep them as our top priority while performing any penetration test. 

Checkout Astra’s Security Audit Checklist for Mobile Applications

Astra's Pentest Dashboard
Image: Astra’s Pentest Dashboard

Conclusion

In a nutshell, there are many reasons why you should be thinking about penetration testing your Android apps. Whether you’re a startup that’s just getting off the ground or a large corporation, the need for penetration testing on Android applications is accurate, and it’s here to stay.

Have any questions or suggestions? Feel free to talk to us anytime! 🙂

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FAQs

1. What is the timeline for Android pentesting?

It takes no more than 7-10 days to complete android penetration testing. The vulnerabilities start showing up in Astra’s pentest dashboard from the 3rd day so that you can get a headstart with the remediation. The timeline may vary with the pentest scope.

2. How much does android penetration testing cost?

The cost of Android penetration testing with Astra’s Pentest suite ranges between $349 and $1499 per scan dpending on the plan and the number of scans you opt for.

3. What makes Astra your best choice for Android pentesting?

1250+ tests, adherence to global security standards, intuitive dashboard with dynamic visualization of vulnerabilities and their severity, security audit with simultaneous remediation assistance, multiple rescans, these are the features that give Astra an edge over all competitors.

4. Do I also get rescans after a vulnerability is fixed?

Yes, you get 2-3 rescans depending on the plan you are on. You can use the rescans within a period of 30 days from initial scan completion even after a vulnerability is fixed.

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Keshav Malik

Keshav is a hacker by heart. He loves playing with fire (code) and loves discovering bugs. Not only in web applications but in all kinds of software. His first introduction to the world of Cyber Security was through bug bounty programs. He quickly made a name for himself as a bug hunter and now actively participates in bug bounty programs. Other than Infosec, he loves creating full stack web applications using cutting edge technologies.
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